Based on the discussion about Demoni +4DGHF , which is a hack of Warhawk with modified graphics, and what Smasher wrote about these hacks and about cracks without intros being sold in Italy. I also got word that in Spain it was done in a similar way.

Maybe you know about other countries this was common?

Also scene groups sometimes modified old games to look a bit different and published them as first releases of new (because widely unknown) games. Cycles +FT is a well known axample for this.